1. Field of the Invention
Aspects of the present invention relate to a supported catalyst and a method of preparing the same, and more particularly, to a highly dispersed supported catalyst containing catalytic metal particles with smaller particle sizes regardless of the type of catalyst support and a method of preparing the same.
2. Description of the Related Art
Conventionally, a supported catalyst refers to a catalyst composed of a catalyst component and a porous catalyst support to which the catalyst component adheres. The porous catalyst support has many pores, and thus a very large surface area. Such a large surface area provides a place in which many catalyst components can be dispersed. The supported catalyst is widely used to accelerate various reactions in various fields.
An example of the supported catalyst is a carbon supported metal catalyst. The carbon supported metal catalyst includes porous carbon particles as a catalyst support and catalytic metal particles as a catalyst component. The carbon supported metal catalyst is also widely used to accelerate various reactions in various fields. An example of the carbon supported metal catalyst is a catalyst contained in an electrode for a fuel cell. More particularly, a cathode and/or an anode of a fuel cell such as a phosphoric acid fuel cell (PAFC), a proton exchange membrane fuel cell (PEMFC), or a direct methanol fuel cell (DMFC) contain the carbon supported metal catalyst which accelerates an electrochemical oxidation of a fuel and/or an electrochemical reduction of oxygen. In this case, carbon particles act as a catalyst support and as an electron conductor. Pt, Pt/Ru alloy, etc. are generally used as the catalytic metal particles.
A method of preparing an anode electrode catalyst by adding a noble metal colloid solution and carbon to an aqueous polymer solution in water at a high temperature in a pressured state is discussed in Japanese Patent Laid-Open Publication No. 2003-123775. In supported catalysts prepared according to the above-described method, as well as in other methods, as the loading amount of catalytic metal particles increases, the average size of catalytic metal particles supported also generally increases. For the reason of this, the improvement of catalytic activity of a supported catalyst through control of the average size of catalytic metal particles and the loading amount of catalytic metal particles is limited.
Moreover, in supported catalysts prepared according to conventional methods, even though the loading amount of catalytic metal particles is reduced, it is difficult to reduce the average size of catalytic metal particles, and thus sufficient dispersion is not obtained. Thus, a technology of improving dispersion while reducing the average size of catalytic metal particles supported on a catalyst support in a loading amount of catalytic metal particles more than or equal to the conventional loading amount of catalytic metal particles needs to be developed.